The perceptual guidance of action and the use of movement to obtain perceptual information are two central aspects of behavior. The Affordance Perception-Action Laboratory (APAL) is a leader in quantitative research on relations between perception and action. Our focus is on the integration of perception and action in the context of affordances. Affordances are relations between properties of the environment and properties of the organism that have consequences for behavior. Affordances are directly relevant to the success of our interactions with the environment. We study movements that are used to gain information about affordances. The venues for our research include laboratory studies in naturalistic situations, virtual environments, and video games, and field studies of perceptual-motor coordination on ships at sea. APAL research straddles the boundary between basic and applied science: Our research on "basic" issues has implications for the design and use of human-machine systems, and our research on "applied" issues has implications for general theories of perception and action.